Showing papers by "Roel F. Veerkamp published in 1994"
TL;DR: No significant feeding system × genetic line interactions were observed for a number of traits, describing milk production, feed intake, efficiency and body tissue mobilisation, when compared as treatment means, indicating that G × E might become of importance in the future, with continued selection for fat plus protein yield.
137 citations
TL;DR: It was concluded that selection on PI for kg fat plus protein is likely to lead to increased margin over food, health and reproduction costs.
Abstract: The aim of this study was to examine the relationship between pedigree index for kg fat plus protein and the financial margins between milk returns and food, health and reproduction costs in individual lactations. Records of milk and milk component production, food intake, health and reproduction were obtained for individual Holstein-Friesian cows over 38 weeks of lactation over a 7-year period, at the University of Edinburgh/Scottish Agricultural College Langhill dairy cattle research centre. Records for a total of 302 lactations were collected. Milk prices, input costs and margins were calculated for individual animals, using 1989/90 values. Regressions of margin over food costs (MF) and margin over food, health and reproduction costs (MFHR) on pedigree index (PI) for kg fat plus protein were all positive and ranged from £2·50± 3·00 per kg PI for MFHR for heifers, to £6·50 ± 2·10 per kg PI for MFHR for all animals. The lower regression for heifers was attributed to higher reproduction costs in animals of higher genetic merit, though the standard error for the regression estimated in this smaller data set was high. Sensitivity analyses showed that the regression coefficients remained very similar, even with ±50% changes in food, health or reproduction costs. It was concluded that selection on PI for kg fat plus protein is likely to lead to increased margin over food, health and reproduction costs.
19 citations
TL;DR: The results were not conclusive enough to develop a selection index, but show that a combination of type, live weight and production are likely to be valuable components of future indices.
8 citations
01 Jan 1994
TL;DR: PTAs for the type traits were used to predict longevity of the cow as a first step towards a 'total merit1 index' and PTAs for milk, fat and protein in an index were used.
Abstract: INTRODUCTION The objective of many dairy formers is to maximise profitability, consistent with the health and welfare of their animals. Clearly longevity of the cow is an important component of profitability (e.g. Rendel and Robertson, 1950). Because no predicted transmitting abilities (PTAs) for longevity (or similar traits) are available in the UK, the objective of this study was to combine PTAs for linear type traits and PTAs for milk, fat and protein in an index. PTAs for the type traits were used to predict longevity of the cow as a first step towards a 'total merit1 index.
1 citations